Performance Engineered Mixtures The Key to Predictable Long-Life Pavement Performance Virginia Concrete Conference Richmond, Virginia March 3, 2017

Transcription

1 Performance Engineered Mixtures The Key to Predictable Long-Life Pavement Performance Virginia Concrete Conference Richmond, Virginia March 3, 2017 Cecil L. Jones, PE Diversified Engineering Services, Inc.

2 PEM - The Path to Implementation What is PEM? Why is it needed? Who has been involved? What has been accomplished to date? PEM Specification Basics Future Plans

3 PEM - The Path to Implementation What is PEM? A program to: Understand what makes concrete last Specify the critical properties and test for them Prepare the mixtures to meet those specifications 3

4 PEM - The Path to Implementation Why are PEM specifications needed? Pavements have not always performed as designed. Premature pavement distress has become more severe with changes in Cements, SCMs, and winter maintenance practices. Allow innovation. Increase sustainability in our mixture designs.

5 PEM - The Path to Implementation Current specifications typically: Do not measure critical engineering parameters. Historically we commonly specify air, slump, and strength, local aggregate requirements. Changes in source materials is difficult. Mixes are often over cemented. Are often built around previous failures thereby introducing unintended consequences. 5

6 VDOT Concrete Pavement Specifications Section 217 Table II-17 Minimum Compressive Strength Laboratory Permeability Minimum Cementitious Content Max w/c ratio Slump & Air Mix Design Options Prescriptive Method following ACI 211 Trial Batch Method Documented Field Experience Method

7 PEM - Goal Require the things that matter Transport properties (everywhere) Aggregate stability (everywhere) Strength (everywhere) Cold weather resistance (cold locations) Shrinkage (dry locations) Workability (everywhere) 7

8 PEM - The Path to Implementation The Vision: Concrete Mixtures that are engineered to meet or exceed the design requirement, are predictably durable, with increased sustainability. Keys: Design and field control of mixtures around engineering properties related to performance. Development of practical specifications. Incorporating this knowledge into an implementation system (Design, Mat ls, Construction, Maintenance). Is validated and refined by performance monitoring.

9 30 DOTs, FHWA, Illinois Tollway, Manitoba TTCC Pooled Fund States

10 PEM - The Path to Implementation NCC Reno meeting April The NCC decided to organize champion states to work with FHWA & leading national researchers to evaluate new testing technologies & develop a PEM framework.

11 PEM Champion States +Manitoba, FHWA MCT & Illinois Tollway

12 PEM - The Path to Implementation Development Team Dr. Peter Taylor, Director CP Tech Center Cecil Jones, Diversified Engineering Services, Inc. Dr. Jason Weiss, Oregon State University Dr. Tyler Ley, Oklahoma State University Dr. Tom VanDam, NCE Mike Praul, FHWA Tom Cackler, CP Tech Center Industry Participants/Reviewers Champion States & ACPA Chapter Execs ACPA National PCA NRMCA

13 PEM - The Path to Implementation What has been accomplished: New testing technologies that measure properties related to critical engineering properties have been integrated into a specification framework. Ongoing evaluation of new test methods. TPF established to assist DOTs with implementation. Solicitation # 1439 AASHTO voted to approve the standard.

14 PEM - The Path to Implementation Provisional AASHTO Standard Practice for Developing Performance Engineered Concrete Pavement Mixtures & Commentary AASHTO PP Will be published in April 2017

15 PEM - The Path to Implementation PEM Mixture Design Parameters (Test the things that matter) Strength Cracking tendency (dimensional stability) Freeze-Thaw durability Resistance to Fluid Transport Aggregate stability Workability* Performance and prescriptive options for each, except strength

16 Test Methods Included Workability VKelly Box SAM Resistivity / Formation Factor Transport and Pore Structure Oxychloride Formation Dual Ring Cracking Test 16

17 PEM - The Path to Implementation Specification Framework Measure properties at the right time Prequalification Process control Acceptance 17

18 Specification Basics Menu specification Not an off the shelf drop in Select from what you want to satisfy the needs you have Intended to work for SHAs and local agencies Intended to respect organizational traditions while offering performance options 18

19 Specification Basics Section Property Specified Test Specified Value Mixture Qualification Acceptance Selection Details Special Notes 6.3 Concrete Strength 6.4 Reducing Unwanted Slab Warping and Cracking Due to Shrinkage (If Cracking is a Concern) 6.5 Durability of Hydrated Cement Paste for Freeze-Thaw Durability 6.6 Transport Properties 6.7 Aggregate Stability 6.8 Workability 19

20 Specification Basics - Strength Section 6.3 Section Property Specified Test Specified Value Mixture Qualification Acceptance Selection Details Special Notes 6.3 Concrete Strength Flexural Strength AASHTO T MPa 600 psi Yes Yes Compressive Strength AASHTO T MPa 3500 psi Yes Yes Choose either or both 20

21 Specification Basics Warping and Cracking Section 6.4 Section Property Specified Test Specified Value Mixture Selection Qualification Acceptance Details Special Notes 6.4 Reducing Unwanted Slab Warping and Cracking Due to Shrinkage (If Cracking is a Concern) Volume of Paste 25% Yes No Unrestrained Volume Change Unrestrained Volume Change ASTM C me at 28 day Yes No Curing Conditions ASTM C , 420, 480 me Restrained Shrinkage AASHTO T 334 crack free Restrained Shrinkage AASHTO TP XXX Probability of Cracking Appendix X1 5, 20, 50% at 91 days Yes at 180 days Yes No No s < 60% f'r at 7 days Yes No as specified Yes No Choose only one Dual ring test is currently under consideration as an AASHTO Provisional Test Method Comm entary Quality control check ~ ~ ~ No Yes Variation controlled with mixture proportion observation or F Factor and Porosity Measures 21

22 Specification Basics Paste Durability Section 6.5 Section Property Specified Test Specified Value 6.5 Durability of Hydrated Cement Paste for Freeze-Thaw Durability Mixture Qualification Acceptance Selection Details Special Notes Water to Cementitious Ratio Fresh Air Content Fresh Air Content/SAM Time of Critical Saturation ~ 0.45 ~ Yes Yes AASHTO T 152, T196, TP 118 AASHTO T 152, T196, TP 118 "Bucket Test" Specification 5 to 8 % Yes Yes 4% Air; SAM 0.2 %, psi Yes Yes Choose Either or Choose only one 30 Years Yes No Note 1 Note 2 Variation controlled with mixture proportion observation or F Factor and Porosity Measures Deicing Salt Damage ~ 35% SCM Yes Yes Are calcium or magnesium chloride used Deicing Salt Damage AASHTO M 224 ~ Topical Treatment Yes Yes Are calcium or magnesium chloride used, use specified sealers Choose one Calcium Oxychloride Test sent to Limit AASHTO < 0.15g CaOXY/g paste Yes No Are calcium or magnesium chloride used 22

23 Specification Basics Transport Properties Section 6.6 Section Property Specified Test Specified Value Mixture Selection Qualification Acceptance Details Special Notes 6.6 Transport Properties Water to Cementitious Ratio ~ 0.45 or 0.50 ~ Yes Yes The required maximum water to cementitious ratio is selected base on freeze-thaw conditions Formation Factor Table or 1000 Choose ~ Yes Yes Based on freeze-thaw conditions. Other criteria could be selected Only One Ionic Penetration, F Factor Appendix X2 25 mm at 30 year Yes, F through r Determined using guidance provided in Appendix X2. 23

24 Specification Basics Aggregate Stability Section 6.7 Section Property Specified Test Specified Value Mixture Qualification Acceptance Selection Details Special Notes 6.7 Aggregate Stability D Cracking AASHTO T 161, ASTM C 1646 ~ ~ Yes No Alkali Aggregate Reactivity AASHTO PP 65 ~ ~ Yes No 24

25 Specification Basics Workability Section 6.8 Section Property Specified Test Specified Value Mixture Qualification Acceptance Selection Details Special Notes 6.8 Workability Box Test Appendix X3 <6.25 mm, < 30% Surf. Void No Modified V-Kelly Test Appendix X mm per root seconds No 25

26 Specification Basics Specification describes process and choices Includes acceptance requirements Includes quality control provisions Contractor submits quality management plan Some minimum requirements listed 26

27 Specification Basics Appendices for new and emerging test methods Cracking and volume change Formation factor and pore solution resistivity Box test V-Kelly test Transport and pore structure Commentary 27

28 Specification Basics Commentary (60 pages) Detailed discussion of each section References for more detailed background 28

29 Quality in the Concrete Paving Process Road Map to the Future of Performance Pooled fund to provide technical support for performance approach to concrete FHWA States Industry Follow-up FHWA initiatives Introduce PEM and a performance approach to concrete acceptance programs Support PEM with Concrete Pavement Trailer Provide additional guidance on tests/implementation Develop quality control guidance

30 Quality in the Concrete Paving Process Quality Control PEM acknowledges the key role of QC in a performance specification Requires an approved QC Plan Requires QC testing and control charts Unit weight Air content/sam Water content Formation Factor Strength Provides guidance for QC Testing targets, frequency, and action limits Guidance will expand on this

31 PEM - The Path to Implementation TPF Work Tasks Implementing what we know: Education, Training & Technical Support Performance Monitoring and Specification Refinement Measuring and Relating Early Age Concrete Properties to Performance

32 PEM - The Path to Implementation TPF Elements Phase 1 with the Scope described 5 years ( ) $3 million Ready to support work by January 1, 2017 Phase 2 (to support performance monitoring) 5 years ( ) $ TBD

33 PEM - The Path to Implementation Proposed Funding Total of $3 million over 5 years FHWA - $200,000/ year = $1m DOTs $15,000/ year = $1.05m Currently (6): Iowa, Ohio, Pennsylvania, South Dakota, Wisconsin, New York Industry - $200,000/ year = $1m

34 Quality in the Concrete Paving Process A Coordinated Approach to Implementation FHWA Agencies Performance Engineered Mixes Industry Academia

35 Quality in the Concrete Paving Process PEM Goal: A Provisional Specification Follow-up FHWA initiatives Introduce PEM and a performance approach to concrete acceptance programs (including QC) Support PEM with Concrete Pavement Trailer and workshop Provide additional guidance on tests/implementation

36 Quality in the Concrete Paving Process Concrete Pavement Performance System Coordinated effort to provide guidance and tools to states and industry to advance concrete Quality Assurance programs in the direction of performance. Mobile Concrete Trailer Video clips QA Toolkit QC framework Implementation Workshops

37 PEM - The Path to Implementation Thank You!